Carbonate ester

Monomers of polycarbonate (e.g. Makrolon or Lexan) are linked by carbonate groups.

[1] Carbonate esters can be divided into three structural classes: acyclic, cyclic, and polymeric.

Both aliphatic or aromatic substituents are known, they are called dialkyl or diaryl carbonates, respectively.

[citation needed] Two main routes to carbonate esters are practiced: the reaction of an alcohol (or phenol) with phosgene (phosgenation), and the reaction of an alcohol with carbon monoxide and an oxidizer (oxidative carbonylation).

[4] A selective membrane can be used to separate the water from the reaction mixture and increase the yield.

However, toxic phosgene is used, and stoichiometric quantities of base (e.g. pyridine) are required to neutralize the hydrogen chloride that is cogenerated.

Annual production of cyclic carbonates was estimated at 100,000 tonnes per year in 2010.

With Grignard reagents carbonate esters react to give tertiary alcohols.

Many industrial production pathways for carbonates are not green because they rely on phosgene or propylene oxide.

[13] Dimethyl dicarbonate is commonly used as a beverage preservative, processing aid, or sterilant.